The present invention relates to wireless networks. More particularly, the invention relates to managing the quality of service (hereafter “QoS”) in a wireless network.
As the use of mobile terminals in wireless networks increases, a serious challenge confronting wireless network service providers is providing and maintaining a high quality of services for their subscribers. In particular, in view of the expanding range of applications for mobile wireless terminals (which will be referred to simply as “terminals” henceforth), including video, audio and text applications, wireless network service providers must allocate sufficient bandwidth and assign appropriate scheduling (e.g., priority) schemes to the traffic of subscribing terminals on the end-to-end path of traffic across the network. The allocation of bandwidth determines the transfer speed of a terminal's application traffic across the network, and the scheduling determines the order of processing and transmission of the different application' traffic at network nodes. Examples of such network nodes include, but are not limited to, base stations and routers. A priority scheme provides an example of such scheduling, by providing one type of traffic precedent over another. For instance, in a network that supports both voice and data traffic, the priority schemes may assign voice traffic priority over data traffic. As a result the nodes in the example network transmit voice traffic packets before they transmit data packets. However, meeting this QoS challenge is made more difficult by the ever-increasing volume of network traffic, and the fact that the terminals are usually roaming around a given network and frequently change their points of connection to the network.
The challenge, noted above, of providing and maintaining the QoS in a wireless network is a difficult one due to the fact that the terminals are often roaming around the network and frequently change their points of attachment to the network.
As an example, consideration is given to a communication between the terminals of two subscribers to the services of a particular network, whereby at least one of the subscriber terminals is a mobile terminal. When a first terminal, which is a mobile terminal, attempts to contact the other subscriber terminal, which may be referred to as the “corresponding terminal”, an end-to-end connection traversing a wireless/wireline infrastructure having sufficient resources, as well as an appropriate scheduling scheme is established between the two terminals. The end-to-end connection begins in the mobile terminal's present location in its present cell, which will be referred to as the “serving cell” hereafter. QoS for such connection is easily maintained so long as the mobile terminal remains in the serving cell.
However, as the mobile terminal moves from its serving cell to another cell, which will be referred to as a “target cell” hereafter, within the network, the network connection to the mobile terminal is handed off from the serving cell to the target cell. The hand off from the serving cell to the target cell interrupts the end-to-end connection between the two terminals, and thus QoS then becomes an issue of concern, for both the terminal users and the network providers.
In order to maintain a high level of QoS and to further ensure minimal disruption of an ongoing communication session, a new end-to-end connection that has sufficient bandwidth and an appropriate priority scheme must be established from the target cell between the mobile terminal and the corresponding terminal as quickly as possible.
Presently, maintaining a high level of QoS for an ongoing communication session by providing sufficient bandwidth and an appropriate priority scheme is not ensured after handoff from a service cell to a target cell due to at least a handoff delay or a bandwidth deficiency in the target cell. A handoff delay occurs when the time taken to set up a new end-to-end connection between the mobile terminal in the target cell and the corresponding terminal is so great that the communication session is disrupted, if not terminated altogether. Further, a bandwidth deficiency in the target cell prohibits completion of the connection between the mobile terminal and its corresponding terminal. As a result the communication session may be terminated because there is no transfer of information between the mobile terminal and its corresponding terminal.
Interruptions in communication sessions, in particular, may often be attributed to the network traffic management system not having sufficient notice of the target cell to which the mobile terminal is moving in time for the handoff to be handled efficiently. As a result, sufficient resources are not assured for the roaming terminal in a timely manner after the handoff to the target cell.
Thus, there is a need for a systems and technique that ensures that a high level QoS is provided and maintained for a mobile terminal's applications as the mobile terminal roams throughout a wireless network, the quality-of-service pertaining to, for example, the provision of sufficient bandwidth and appropriate priority schemes.